Venturi flow sensor

Abstract

A venturi flow sensing method, system, and apparatus. A tube or chamber may be tapered from a larger to smaller diameter to create a venturi region within the tube or chamber. The venturi region causes a local increase in flow velocity. The change in velocity creates a local change in pressure which is, in turn, used to drive flow through a parallel bypass tube or chamber. Inside this bypass, a flow sensor can be located, and in some cases, a pressure sensor as well. The flow is then either exhausted back into the original tube or the bypass tube may alternatively dead end. In either case, flow can be measured without causing a significant overall pressure drop in the system.

Description

technical field [0001] The present invention generally relates to flow sensors. The invention also relates to the measurement of air flow and pressure. The invention additionally relates to flow sensors for use in medical applications. Background technique [0002] Medical devices such as ventilators and CPAP (Continuous Positive Airway Pressure) machines are designed to provide air to the patient to foster proper breathing. For example, ventilators are designed to move air in and out of a person's lungs to mechanically assist breathing (eg, life support machines). A similar device is a respirator, which is used to assist or control breathing. Other similar machines facilitate breathing in persons with impaired diaphragm function. These and other mechanical breathing devices often require significant pressure changes to accurately measure air flow. However, such pressure changes are often uncomfortable for the patient and do not promote optimal fan performance. [0003...

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However, such devices are usually expensive

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